Just read your post regarding detecting at the beach. Your best bet, for the price range you desire, is to find a used detector. I detect several times weekly at the ocean along the NC coast. Many detectors are not water proof, this you want. Such as the previous reply, headphones are really useful. A long handled scoop will make life so much easier. I see the newbies daily with their little garden trowel, up and down digging, that get's old.
For the ocean I use a Minilab Excalibur 1000, the wife uses a White's Beach hunter 300. For hard ground I use a White's DFX300. These three machine range in price from $950.00-$1,400.00.
About one month ago I recovered on diamon/wedding band that measured 1.69C, appraised at $5,500.00-$6,000.00. Year to date we have located 14 rings (gold), 12 silver half dollars, 1 silver dollar, 3 gold chains, about one roll of silver quarts and dimes and a whole bunch of clad coins.
I have seen some real nice machines on Craigs List for a fraction of the cost.
Most respectfully
Larry
Deputy347k9 Retired
MSgt US Marine Corps Retired